On May 13 2005 an open workshop of the eInfrastructures policy initiative was held in Amsterdam. The e-Infrastructures Workshop consisted of a plenary meeting (to set the context for the whole workshop), a real workshop part (where subjects were discussed in more depth in smaller groups) and a final plenary (where the results from the parallel sessions are summarised). Workshop sessions were chaired by a.o. Kees Neggers (SURFnet), Gigi Karmous-Edwards (MCNC), Hans Doebbeling (DANTE), Dany Vandromme (Renater), Frank Harris (CERN), Manuel Delfino (PIC), Kees Stuurman (UvT), Berend Smit (CECAM) and John Gordon (CCLRC).